(1) Field of the Invention
The invention relates to an integrated circuit for controlling an electric motor, which has a primary component having a coil and a permanently magnetic secondary component displaceable relative to and cooperatively coupled via an air space to said primary component, with a semiconductor substrate in which is integrated a microcontroller and/or a pre-amplifier for controlling the coil of the electric motor.
(2) Description of Related Art P Such a circuit integrated in a first semiconductor chip is commercially available under the type designation 908E625 from the manufacturer Freescale™ Semiconductor, Inc., Arizona, USA. It has a semiconductor substrate, in which a microcontroller is integrated, which comprises a programmable, nonvolatile memory, a timer, a communication interface, an analog-to-digital converter, and a serial-parallel interface. The first semiconductor chip is arranged in a plastic housing together with a second semiconductor chip, in which are integrated a pre-amplifier and final stage transistors for three half bridges for controlling a three phase coil of an electric motor. For electrical contact, provision is made on the plastic housing for connecting terminals, which are connected to contact sites on the semiconductor chip via contact wires. Three connecting terminals are connected to the three half bridges. The three phase terminals of the coil arranged on the primary component of the electric motor are connected to these connecting terminals. A fourth connecting terminal is connected to the neutral point of the coil. The electric motor has three Hall sensors, which are arranged on the primary component at intervals of 120° and detect the magnetic field of the permanently magnetic pole of the secondary component moving past the Hall sensors. The measurement signal output ports of the Hall sensors are in each case connected to an allocated connecting terminal of the first semiconductor chip. By means of the microcontroller, the given position of the secondary component relative to the first component is determined using the Hall sensor measurement signals, and the coil is controlled relative to the position via the pre-amplifier and the half bridges, in order to generate a relative movement between said primary and said secondary components. The electric drive with the semiconductor chip, however, is still comparatively complex and expensive.